Editing Langjökull

{{Short description|Glacier in Iceland}}
{{About|the Langjökull ice cap|Langjökull volcanic system|Oddnýjarhnjúkur-Langjökull volcanic system}}
{{Infobox glacier
| name          = Langjökull
| other_name    = Lángjökull
| photo         = Image:Islande Langjokull.jpg
| photo_caption = [[Þórisjökull]] in the foreground, part of Langjökull in the background
| type          = Ice cap
| location      = [[Iceland]]
| coords        = {{coord|64.6918|-20.1968|type:glacier|display=inline, title}}
| area          = 
| length        = 
| thickness     = {{cvt|580|m}}<ref name=Björnsson2017/>
| terminus      = from the north, Baldjökull, Pjófadalajökull, Hengibjörg, Leiðarjökull, Kirkjujökull, Norðurjökull, Skriðufell, Suðurjökull, Skálpanes, Jarlhettur, Eystri-Hagafellsjökull, Hagafell, Vestri-Hagafellsjökull, Lónsjökull, [[Geitlandsjökull]], Svartárjökull', Flosajökull, Þrístapajökull<ref name=gn>{{cite book|chapter =Geographic Names of Iceland’s Glaciers:Historic and Modern|url =https://pubs.usgs.gov/pp/1746/pdf/PP1746_pg1-42_fig1-10_lowrez.pdf|first1=Oddur|last1 =Sigurðsson|first2 =Richard S.|last2 =Williams|year=2008|title =Satellite Image Atlas of Glaciers of the World series (U.S. Geological Survey Professional Paper 1386-D|editor1=Richard S. Williams Jr.|editor2=Jane G. Ferrigno|access-date=18 May 2024}}{{rp|pp=17,19}}</ref><ref name=pope2016>{{cite journal|last1 =Pope|first1 =A.|last2 =Willis|first2 =I.C.|last3 =Palsson|first3 = F.|last4 =Arnold|first4 =N.S.|last5 =Rees|first5 =W.G.|last6 =Björnsson|first6 =H.|last7 =Grey|first7 =L.|year =2016|title =Elevation change, mass balance, dynamics and surging of Langjökull, Iceland from 1997 to 2007|journal =Journal of Glaciology|volume =62|issue =233|pages =497-511|bibcode =2016JGlac..62..497P|doi =10.1017/jog.2016.55}}</ref>{{rp|499}}
| status        = Retreating<ref name=pope2016/>{{rp|503}}
| map_image     = {{maplink|frame=yes|frame-align=center|frame-width=260|frame-height=260|frame-long=-20.2|frame-lat=64.7|zoom=8|raw={{Wikipedia:Map data/Vatnajökull}}|text=Map of Langjökull ice cap showing its named glacial catchments (light grey shading with white outline). Clicking on the map to enlarge it enables mouse over that allows identification of individual named glacial catchments in Iceland.}}
}}

'''Langjökull''' ({{IPA|is|ˈlauŋkˌjœːkʏtl̥|audio=Langjökull pronunciation.ogg}}, [[Icelandic language|Icelandic]] for "long glacier") is the second largest [[ice cap]] in [[Iceland]] ({{cvt|870|km2}}),<ref name=Björnsson2017>{{cite book|last1= Björnsson|first1 =H.|year =2017|chapter= Glaciers of the Central Highlands|title =The Glaciers of Iceland Atlantis Advances in Quaternary Science| volume = 2|publisher =Atlantis Press, Paris|doi =10.2991/978-94-6239-207-6_6|isbn =978-94-6239-207-6|pages =275–336}}</ref> after [[Vatnajökull]]. It is situated in the west of the Icelandic interior or [[Highlands of Iceland]] and can be seen clearly from [[Haukadalur]]. It covers the higher parts of the [[Oddnýjarhnjúkur-Langjökull volcanic system|Langjökull volcanic system]].

Its volume is {{cvt|195|km3}} and the ice is up to {{convert|580|m|abbr=on}} thick. The highest point of the ice cap (at ''Baldjökull'' {{IPA|is|ˈpaltˌjœːkʏtl̥|}} at the northern end of Langjökull) is about {{convert|1450|m|abbr=on}} above sea level.

In the past, the largest recorded surface area was in 1840.<ref name="sciencedirect.com">{{cite journal |last1=Flowers |first1=Gwenn E. |last2=Björnsson |first2=Helgi |last3=Geirsdóttir |first3=Áslaug |last4=Miller |first4=Gifford H. |author-link4=Gifford H. Miller |last5=Clarke |first5=Garry K.C. |year=2007 |title=Glacier fluctuation and inferred climatology of Langjökull ice cap through the Little Ice Age |journal=Quaternary Science Reviews |volume=26 |issue=19–21 |pages=2337–2353 |bibcode=2007QSRv...26.2337F |citeseerx=10.1.1.596.2710 |doi=10.1016/j.quascirev.2007.07.016}}</ref>

==Situation and form==
{{See also|Volcanism of Iceland}}

The glacier is roughly parallel to the direction of the country's active volcanic zone: north-east to south-west. It is about {{convert|50|km|abbr=on}} long and {{convert|15|to|20|km|abbr=on}} wide, and has a slightly narrower point roughly between the lake [[Hvítárvatn]] on the [[Kjölur]] mountain road to the east and the Þrístapajökull glacier to the west, near another smaller glacier, [[Eiríksjökull]], which is not quite connected to Langjökull. It is the nearest large glacier to [[Reykjavík]].

The area of the glacier includes some mountains, e.g. ''Jarlhettur'' ({{IPA|is|ˈja(r)tl̥ˌhɛhtʏr̥|}}; "The earl's hat") on the east side of Langjökull, a [[palagonite|palagonitic]] mountain range, which originated in a [[fissure vent]] under a glacier during the [[Last Glacial Period|Ice Age]].

The mountain ''Skríðufell'' {{IPA|is|ˈskriːðʏˌfɛtl̥|}} ({{convert|1235|m|abbr=on}}) is situated on the east, above lake [[Hvítárvatn]]. Other mountains on the eastern side of Langjökull are ''Fjallkirkja'' {{IPA|is|ˈfjatl̥ˌcʰɪr̥ca|}} ({{convert|1177|m|abbr=on}}), ''Þursaborg'' {{IPA|is|ˈθʏr̥saˌpɔrk|}} ({{convert|1290|m|abbr=on}}) and ''Péturshorn'' {{IPA|is|ˈpʰjɛːtʏr̥sˌhɔ(r)tn̥|}} ({{convert|1370|m|abbr=on}}).<ref>Kortabók Mál og Menningar, Reykjavík 2005, pp.48/49 and 55/56, icel.</ref>

A little to the east of ''Fjallkirkja'' is the hut of the Icelandic Glacier Research Society (also called Jöklarannsóknarfélag in the {{ill|Jöklarannsóknafélag Íslands|is}}), which includes scientists as well as interested amateurs.<ref>Íslandshandbókin. Fyrra bindi. Reykjavík 1989, pp. 111 f.</ref>

==Glaciers in the area==
[[Image:Langjökull Abyss.jpg|thumb|A [[Moulin (geology)|moulin]] in the Langjökull glacier]]

A number of outlet glaciers reach down from Langjökull to the valleys and plains below. However various different names exist for these outlet areas and there are outlet areas that do not have glacial names. The outlets include ''Norðurjökull'' {{IPA|is|ˈnɔrðʏrˌjœːkʏtl̥|}} and ''Suðurjökull'' {{IPA|is|ˈsʏːðʏrˌjœːkʏtl̥|}} to the east, separated by the ''Skriðufell'' glacier outlet area; ''Eystri-Hagafellsjökull (Hagafellsjökull eystri)'' {{IPA|is|ˈeistrɪ-|}} at the southern end of Langjökull which is separated from ''Suðurjökull'' by the ''Skálpanes'' and ''Jarlhettur'' glacier outlet areas; the mountain ''Hagafell'' {{IPA|is|ˈhaːɣaˌfɛtl̥|}} which is also a small outlet area between ''Eystri-Hagafellsjökull'' and ''Vestri-Hagafellsjökull (Hagafellsjökull vestari)'' {{IPA|is|ˈvɛstrɪ-ˌhaːɣaˌfɛlsˌjœːkʏtl̥|}}; ''Lónsjökull'' (''Lónjökull'') between it and ''[[Geitlandsjökull]]'' ({{cvt|1395|m}}) an outpost to the south-west, with its glacier covering a [[tuya]]; ''Svartárjökull'', ''Flosajökull'' (''Flosakarðsjöklar'' catchment), ''Þrístapajökull'' {{IPA|is|ˈθriːˌstaːpaˌjœːkʏtl̥|}} and ''Baldjökull'' to the west. From the north east on the far side of the ''Baldjökull'' catchment there is ''Pjófadalajökull'', ''Hengibjörg'', ''Leiðarjökull'' and ''Kirkjujökull'' catchments. The old icecap marginal glacier name of Bláfellsjökull for Suðurjökull is no longer used.<ref name=gn/><ref name=pope2016/>{{rp|499}}{{efn|The following outlet glacier names mentioned in text are not currently official,<ref>{{cite web|title=National Land Survey of Iceland-Mapviewer (Kortasja-Landmælingar Íslands) |url=https://kortasja.lmi.is/mapview/ |access-date=19 May 2024}}</ref> but are used in  acaedemic papers - Lónjökull as Lónsjökull,<ref name=pope2016/> Hagafellsjökull eystri,<ref name=gn/> Hagafellsjökull vestari,<ref name=gn/> Svartárjökull,<ref name=pope2016/> and Flosakarðsjöklar.<ref name=pope2016/> The names Regnbúðarjökull and Skjaldbreiðarjökull are no longer used and are not official either.<ref name=gn/>}}
Research shows that the outlet glaciers ''Norðurjökull'' and ''Suðurjökull'' reached as far as lake Hvítárvatn until about 1900 but have retreated rapidly since then.<ref name="sciencedirect.com"/>

==Water flow and development of the glacier==
Despite the size of Langjökull, not many rivers directly originate there. However research has shown that large quantities of water flow in sub-surface streams to lake [[Þingvallavatn]] (some {{cvt|50|km}} to the south and easily accessible to tourists) and reappear in springs in and around the lake, while the same happens on the west side, giving rise to various tributaries of the [[Hvítá, Árnessýsla|Hvítá River]] as well as some rivers flowing north towards [[Húnaflói]]. Thus many of the hot springs in the [[Borgarfjörður]] region (near the estuary of the Hvítá on the west coast), such as [[Deildartunguhver]], receive ground water from Langjökull.

The same is true for the lake [[Hvítárvatn]] to the east: two-thirds of its waters appear to come from Langjökull by underwater channels.<ref name="sciencedirect.com"/>

Langjökull is shrinking quite fast, and some researchers believe that it will disappear in about 150 years if climate change continues at its recent pace.<ref>{{cite web|last1 =Björnsson|first1 =H.|last2 =Aðalgeirsdóttir|first2 =G.|last3 =Guðmundsson|first3 =S.|last4 =Jóhannesson|first4 =T.|last5 =Pálsson|first5 =F.|last6 =Sigurðsson|first6 =O.|year =2006|title =Climate change response of Vatnajökull, Hofsjökull and Langjökull ice caps, Iceland|publisher=European Conference on Impacts of Climate Change on Renewable Energy Sources, Reykjavik, Iceland.|access-date=2024-05-01|url =https://www.researchgate.net/profile/Sverrir-Gudmundsson/publication/242197625_Climate_change_response_of_Vatnajokull_Hofsjokull_and_Langjokullice_caps_Iceland/links/0deec52a5bbc8bd043000000/Climate-change-response-of-Vatnajoekull-Hofsjoekull-and-Langjoekullice-caps-Iceland.pdf}}</ref>
==Volcanism==
[[Image:Hveravellir 01.jpg|thumb|Hveravellir]]
[[Image:Hveravellir 02.jpg|thumb|At Hveravellir]]
Under Langjökull there are volcanoes with several components. The calderas can easily be seen from the air. The best known of these is [[Hveravellir]] with its hot spring and high temperature area to the east of the glacier. During an Ice Age some [[shield volcano]]es of this system covered the plains with lava in the region of today's [[Kjölur]] mountain road: the ''Kjalhraun'' ({{IPA|is|ˈcʰalˌr̥œyːn|}}; ''hraun'' means "lava field"). Some of this lava field is about 7,800 years old.<ref>{{cite gvp|name=Oddnýjarhnjúkur-Langjökull|vn=371080|access-date=2024-05-01}}</ref>

A smaller volcanic system lies to the north-west of the glacier in the {{ill|Arnarvatnsheiði|is}} {{IPA|is|ˈa(r)tnarˌvasːˌheiːðɪ|}}, north of the glacier [[Eiríksjökull]]. About 1,000 years ago, the craters of this system produced the lava field ''Hallmundarhraun'' {{IPA|is|ˈhatl̥ˌmʏntar̥ˌr̥œyːn|}} which extends some {{cvt|50|km}} westward into the valley of the Hvítá, and is traversed by underground streams which emerge at the waterfalls of [[Hraunfossar]] not far from [[Húsafell]].

Another volcanic system to the south-west of Langjökull is [[Presthnúkur]], named after its [[central volcano]], a [[rhyolite]] [[lava dome|dome]] with a high temperature area at its foot. Its fissures extend under Langjökull.

Volcanically, the region is relatively quiet, compared to other regions in Iceland, with just 32 eruptions in the last 10,000 years.<ref>[http://www.mantleplumes.org/Penrose/PenPDFAbstracts/Jakobsson_Sveinn_abs.pdf Sveinn Jakobson u.a., Volcanic systems and segmentation of the plate boundaries in S-W-Iceland]</ref>

==Highland roads==
[[File:Langjökull from Gullfoss.jpg|right|thumb|The southeastern tongue of Langjökull, as seen from the [[Gullfoss]] waterfall.]]
Two highland tracks, open in the summer months, lead alongside this glacier: the [[Kaldidalur]] and [[Kjölur]] tracks.

The former (road 550) runs along the west of Langjökull, between it and the small [[Ok (glacier)|Ok]] glacier. To the south it leads towards [[Þingvellir]] and Reykjavík, while to the north it leads to the Hvítá valley which leads down towards Borgarnes. Kaldidalur is no longer classified by the Icelandic road authorities as an F-road. Nevertheless, rental car companies forbid their clients to drive on the road with other cars than four-wheel drives. 
Road F551 goes right to the edge of the glacier from Kaldidalur.

The latter (road F35) runs along the east side of Langjökull, between it and [[Hofsjökull]]. It is the main route across the interior between the main population centres in the SW and the N of the country, but nevertheless traffic is extremely sparse.

==Tourism==
Langjökull attracts visitors who are captivated by its immense size and natural beauty. The glacier offers a unique experience for adventure enthusiasts and nature lovers alike. With its easily accessible location in the Icelandic interior, Langjökull provides opportunities for various activities, such as glacier hiking, snowmobiling, monster truck ride, and exploring natural ice caves and man-made tunnels. These experiences provide a different perspective of the glacier and its surroundings, enhancing the overall visit to Langjökull.

Located near popular tourist routes like the [[Golden Circle (Iceland)|Golden Circle]], Langjökull holds a prominent position in Iceland's tourism industry. Its significant contribution to the surrounding natural wonders, such as [[Gullfoss|Gullfoss waterfall]] and [[Geysir]]'s geothermal area, adds to its allure. The glacier's proximity to these iconic sites makes it a sought-after destination for travelers seeking to witness the awe-inspiring effects of glacial forces on the landscape.

It is important to note the importance of responsible tourism practices to preserve and protect Langjökull. Visitors are encouraged to respect the environment and follow sustainable guidelines to ensure the long-term preservation of this remarkable glacier.
==In popular culture== 
The glacier is featured in the final scene of the 1999 animated film ''[[The Iron Giant]]'', directed by [[Brad Bird]], where the titular Giant's parts, scattered by his destruction at the film's climax, converge on his head to begin reassembling him.

The first chapter of the thriller novel ''The Last Orphan'' by Gregg Hurwitz takes place on top of the glacier.

==See also==
* [[Geography of Iceland]]
* [[Iceland plume]]
* [[List of glaciers]]
* [[List of glaciers of Iceland]]
* [[List of islands of Iceland]]
* [[List of lakes of Iceland]]
* [[List of rivers of Iceland]]
* [[List of volcanoes in Iceland]]
* [[List of waterfalls of Iceland]]
== Notes ==
{{Noteslist}}

== References ==
{{Reflist}}

==External links==
{{Commons|Langjökull}}
*[https://icelandicvolcanoes.is/?volcano=LAN Langjökull] in the [[Catalogue of Icelandic Volcanoes]]
*[http://www.isafold.de/langhof97/img_langjokull.htm Photo of Langjökull]
*[https://www.sciencedirect.com/science/article/pii/S0277379107001965 Gwenn E. Flowers, Helgi Björnsson, Áslaug Geirsdóttir,  Gifford H. Miller and Garry K.C. Clark:Glacier fluctuation and inferred climatology of Langjokull through the little Ice Age. in: Quaternary Science Reviews, Vol. 26, 2007]
*[http://en.vedur.is/earthquakes-and-volcanism/earthquakes/langjokull/  Erdbebenüberwachung am Langjökull]
*[http://www.mantleplumes.org/Penrose/PenPDFAbstracts/Jakobsson_Sveinn_abs.pdf Sveinn Jakobson u.a., Volcanic systems and segmentation of the plate boundaries in S-W-Iceland]
*[http://www.skimountaineer.com/ROF/ROF.php?name=Langjokull  Skiing on the glacier]

{{Glaciers of Iceland}}
{{Authority control}}

{{DEFAULTSORT:Langjokull}}
[[Category:Highlands of Iceland]]
[[Category:Bodies of ice of Iceland]]
[[Category:Ice caps]]
[[Category:Volcanic systems of Iceland]]
[[Category:West Volcanic Zone of Iceland]]